New information can be introduced in discourse through different strategies, including syntactic and prosodic ones. This project provides an account of the syntactic and intonational strategies used for focus-marking in Peninsular Spanish, Mainstream American English and L2 Spanish using parallel experimental designs and a unitary method of analysis within the Autosegmental-Metrical framework for the study of intonation. It provides a comprehensive description of specific phonological categories and their phonetic implementation not only in monolingual speech, but also as they develop in the L2 grammar of Spanish learners with different experiences with the target language, following the premises of the L2 Intonation Learning Theory (LILt). Additionally, the perception of L2 intonation by native speakers was examined using an acceptability judgment task. Findings show that the intonational grammars of Spanish learners develop despite the lack of formal instruction, which allows them to produce native-like contours in certain contexts even if they have not been immersed in the target language for an extended period of time. This development is, nonetheless, constrained by different linguistic (i.e. transfer, universal patterns) and individual factors (i.e. onset of acquisition, proficiency). Furthermore, results from the acceptability judgment task suggest that learners’ communicative intentions are correctly identified by native speakers when they use target-like contours, but they are misinterpreted when they fail to produce a target-like contour. This study contributes to the understanding of the role of transfer, linguistic interdependencies and interlanguage representations in the development of intonational grammars. Moreover, it shows that the acquisition of intonation is not so different from the L2 acquisition of morpho-syntax or segmental phonology and may be examined through similar approaches, including feature-based ones.